This application claims the priority of German Patent Application Serial No. 100 14 935.9, filed Mar. 20, 2000, the subject matter of which is incorporated herein by reference.
The present invention relates, in general, to an apparatus for the continuous, chipless separation of individual, identical disk-shaped blanks or rods from round bar-shaped workpieces.
German patent publication DE-OS 16 02 950 discloses a method and apparatus for separating individual rings from tubular workpieces and describes a separating and rolling device having at least two cutting rollers in opposite disposition. The cutting rollers have coils which progressively increase in height from the start towards the end to thereby form a narrowing intermediate space. The tubular workpiece is supported on the inside by an inserted mandrel which projects on both sides beyond the workpiece, with their projecting ends rolling on one of both rollers.
International publication WO 99/07495 describes an arrangement with a separating and rolling device and an inlet gutter positioned upstream of the separating and rolling device. A feed unit advances the workpiece from the inlet gutter to the separating and rolling device and imparts a rotation upon the workpiece. Arranged immediately upstream of the separating and rolling device is an induction heat unit with an anterior buffer zone. The separating and rolling device has at least two cutting rollers arranged about the tubular workpiece being worked on and driven in a common direction. The cutting rollers are coupled to one another in a positive manner and have thread-like cutting edges.
It would be desirable and advantageous to provide an apparatus that implements a continuous, chipless separation of individual, identical blanks from a solid workpiece such as round bars.
The present invention provides for a separating and rolling device which has at least two cutting rollers for processing a solid round workpiece, with each of the cutting rollers having a coil and including a separating portion, wherein the coil of at least one of the cutting rollers has in the separating portion a height which is equal or slightly greater than the radius of the workpiece, and wherein the coil of the other one of the cutting rollers is so configured as to avoid in the separating portion a collision with the coil of the one of the cutting rollers.
In accordance with one embodiment of the present invention, the two cutting rollers are disposed in opposite relationship and interconnected in positive manner and driven in a common direction. The coils of both cutting rollers have in an entry portion and a primary portion up to the separating portion a height which increases to a level that, measured from a tip of the coil, slightly exceeds the radius of the workpiece being cut. To prevent a collision in the separating portion, the confronting cutting edges of the coils of the both cutting rollers have tip configurations pointing in opposite directions.
There are many variations that generally follow the concept outlined here for preventing a collision of the coils of opposing cutting rollers in the separating portion. One option may include a configuration in which the coil of only one of the cutting rollers increases in height while the height of the coil of the other one of the two cutting rollers remains constant. Another option may include a configuration in which the height of the coils of the cutting rollers increases in an alternating and oscillating manner in the separating portion.
When the separating and rolling device has only two cutting rollers, it is difficult to keep a precise central guidance of the round solid workpiece as a consequence of the availability of a geometrically very small gap. To address this problem, it is proposed in accordance with the present invention, to provide a guiding gib which is configured as endless sliding shoe guided in chain links. In this manner, the round workpiece is secured in the spaces between the coils and conjointly pulled by the coils of the cutting rollers as a result of the coil pitch.
According to another feature of the present invention, the guidance of the round workpiece may also be implemented by a separating and rolling device having three cutting rollers. In one variation, the three cutting rollers have a same base diameter, are driven in a common direction, interconnected in a positive manner and arranged in 120xc2x0 offset disposition, thereby defining a top roller and two bottom rollers. Each of the cutting rollers has a coil which increases steadily in height in the entry portion and the primary portion, wherein only the coil of the top roller has in the separating portion a height which increases to a level that slightly exceeds the radius of the workpiece to be cut. A collision of the coil tip of the top roller with the surface of both bottom rollers can be avoided by configuring the radius r of the workpiece according to the requirement rxe2x89xa70.366 R wherein R is the base radius of the three cutting rollers.
It is also possible to so approach both bottom rollers as to realize a contact therebetween, so that the offset arrangement of the cutting rollers is less than 120xc2x0. This configuration allows a separation of a round workpiece of even smaller radius r, whereby in this case rxe2x89xa70.2601 R.
A further minimization of the initial diameter of the round workpiece can be realized when the three cutting rollers have different base diameters, whereby the top roller has a greater base diameter than the identical base diameters of the bottom rollers.
According to another feature of the present invention, the bottom rollers may coast idly, i.e. is not driven separately, or may be driven separate from the top roller, with matching rotational speed.